Steam-engine.



M. A. GREEN.

STEAM ENGINE.

APPLIOATION FILED 0GT.14, 1911.

Patented NOV. 26, 1912.

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WIM/8858 ATTH/VEYS COLUMBIA PLANDGRAPH CO.,WASHIN1TON. D. c.

MARTIN A. GREEN, OF PHILADELPHIA, PENNSYLVANIA.

STEAM-ENGINE.

Specification of Letters Patent.

Patented Nov. 26, 1912.

Application filed October 14, 1911. Serial No. 654,771.

' To all whom t may concern.-

Be it known that I, MARTIN A. GREEN, a citizen of the United States, and a resident of Philadelphia, in the county of Philadelphia, State of Pennsylvania, have invented a new and useful Improvement in Steam-Engines, of which the following is a specification.

My invention is an improvement in reciprocating steam engines, and has for its object the provision of simple economical, and easily operated means for varying the clearance at each end of the cylinder, in order to increase or diminish the compression, and without affecting the total length of the cylinder or the total length of the piston.

In the drawings :#Figure l is a vertical longitudinal section of an engine constructed in accordance with the improvement, and Fig. 2 is a similar view of a modied form.

It has been found practically impossible to design an engine of the reciprocating type, either stationary, locomotive or marine, with proper clearance to give the proper amountof compression to suit all conditions, whether condensing or non-con densing, variable steam pressures and variable speeds, without adjustable exhaust valves (when exhaust valves are used). It is just as impossible to design an engine ot the center discharge or exhaust type to produce the same effects without an adjustment to increase or diminish the clearance, so as to regulate the compression to suit all con-- ditions.

Then an engine is running condensing, a vacuum is formed in the cylinder and practically all of the steam is withdrawn therefrom, when the piston uncovers the exhaust ports. VVhe-n the engine is running noncondensing some steam will remain in the cylinder after the ports have been uncovered, and if the clearance between the piston and the cylinder heads is slight, too great an amount ot steam will remain at atmospheric pressure, and there will be danger that the cylinder heads will be broken or blown out.

In the present invention, a means is provided for increasing or diminishing the clearance at the ends of the cylinder, in order to obtain the proper compression at the ends thereof. When the improved engine is running condensing, the clearance can be reduced to a minimum, because the clearance that would naturally occur it exhaust valves were used, will be saved. In the usual type of engine where steam admission and exhaust valves are used, the exhaust valves are at the ends of the cylinder and the said valves must begin to open long before the piston is at its journeys end in either direction, thus cutting down the mean effective pressure in the cylinder, and at the same time permitting (when the exhaust valves are opened) the most eective portion of the steam to exhaust into the atmosphere, that is, that portion of the steam which is nearest the ends of the cylinder and as a consequence the hottest.

ln the improvement, the piston acts as an exhaust valve and the exhaust occurs after the piston has traveled practically the entire length of its stroke, and since the exhaust occurs near the longitudinal center of the cylinder, the least effective portion of the steam, that is, the coolest, is ejected, together with a considerable portion of the condensed steam, while the hottest and the most effective portion thereof is retained for compression.

ln the improvement, neither the length of the piston nor the length of the cylinder is affected. For this reason it does not mat ter at what point the engine cuts oft, or what method of adjustment is used, since the piston always opens the ports in the center of the cylinder at the right and proper time to relieve the exhaust steam. This is true whether the adjustment' is in the piston or in the cylinder head.

The improved engine is cheaper in first cost, since the cylinder is of such form and design that it may be cheaply cast, and cheaply tted up, and since exhaust valves and exhaust apparatus are eliminated. It is also more economical in the operation and upkeep because of the simpler construction and fewer parts. In addition since the steam follows the piston to approximately its journeys end practically all of the expansion of the steam is utilized with one cylinder, thus making a one cylinder engine as economical and as effective as a compound engine, and without the expense of a second cylinder.

In the embodiment of the invent-ion shown in Fig. l, the cylinder 1 of the engine is supported by a base or pedestal 2. The cylinder is provided intermediate its ends, and at approximately its longitudinal center, with an annular series of exhaust opening or slots 3, and with an annular chamber 4 in the cylinder wall with which the slots 3 communicate. The exhaust chamber extends upon both lsides of the series of slots toward the ends of the cylinder, and forms a steam jacket, acting to prevent condensation at this point, and to retain the steam in heated condition. The chamber opens into the pedestal as shown at 4a. rlhe ends of the cylinder are closed by heads 5 and 6, the former being secured in place by cap screws 7, and the said heads 5 and 6 are cup-shaped as shown, and the cylinder is provided with inlet ports 8 and 9 at each end, and adjacent to the head. The said openings 8 and 9 communicate with a chamber l0 at the upper part of the cylinder', and extending longitudinally thereof, through valve openings 11' and 12, respectively, each opening being encircled by a seat with which the inlet valves 13 and 14, respectively, coperate. At the lower part of the cylinder, relief ports 17 and 18 are provided,

each of which is provided with a valve casing 15 and 16, respectively, and the casings are controlled by valves 19 and 20, re-

spectively. Each valve is held in closed `position by means of a spring 17a, and the tension of each spring may be adjusted by means of the stem 13a bearing against the outer end of the spring. The casings also communicate with each other by means of a pipe 21.l rlhe valves 19 and 2O are relief valves and are designed to prevent injury to the cylinder from o-verpressure. Should the pressure in either end of the cylinder pass a predetermined point, determined by the tension of the spring, the valves will open, permitting a portion of the fluid to escape, thus relieving the pressure. The point at which the valves open may be regulated by means of the springs. A valve stem 22 is connected to each valve 13 and 14, and each stem extends upwardly through a easing 23 secured to the cylinder over an opening 24 leading from chamber 10 before mentioned. Each casing 23 is provided with a transverse passage 25 extending parallel with the axis of the cylinder, and each stem is provided with a stirrup or hanger 26 at the said opening. A roller 27 is journaled in each stirrup, and a spring 23 is arranged between the upper end of each stirrup and a cap 29 in the top of the casing. Each cap is engaged by a screw 30 threaded through t-he top of the casing, and by means of the screws the tension of the springs may be adjusted to vary the pressure on the valves. A slide bar 31 is movable through the openings 25, and the said bar is provided with a cam 32 coperating with Y each roller for lifting the valve connected ing 25, and each end of each plate is flanged i downwardly, as indicated at 33. A strap is secured to the edge of each flange by screws 40, and the inner edge of each strap engages beneath a shoulder 41 on the casing to hold the cap plate in place. The cams 32 are so arranged that the valves 13 and 14 will be lifted alternately, and the shaft 34 is rot-ated from the engine at a speed such that the valves will be operated at the proper time. Each of the heads 5 and 6 is, as before stated, cup-shaped, so that a recess is formed at each end of the cylinder in the head. A movable head 43 or 44 is arranged in the recesses of the respective heads 5 and 6, and each head tits closely in the recess and is provided with suitable packing rings 45a. Each head is concave-convex and is arranged with its convex face inwardly, and the fixed heads are shaped to fit the movable heads. A screw threaded pin or bolt 45 is threaded through a central opening in head 43, and at each side of the head is provided with a collar 46. The bolt is reduced at its outer end and the reduced portion passes through a central opening in t-he lixed head 5 and is engaged by a nut 47. The movable head 44 is provided with a central opening for receiving the piston rod 48 and a sleeve 49 which encircles the rod. The sleeve is externally threaded adjacent to the head, and the central opening of the head is provided with a thread fitting the thread of the sleeve. The sleeve is prevented from longitudinal movement by means of an enlargment 49a on the sleeve, the said enlargement being received within a recess 6a of the adjacent head 6. Packing plates 49b are arranged within the recess, the said plates being shaped to fit the enlargement, and a plate 49c is secured to the inner face of the head 6 over the recess. rlhe sleeve may be engaged by means of a spanner or other tool to turn the same to move the head 44 toward or from the center of the cylinder.

The piston is composed of two sections 50 and 51, spaced apart from each other. and arranged on a reduced portion 52 oi' the rod. The outer face of each section is shaped to fit the inner face of the adjacent movable head, and the said sections are held in spaced relation by means of a sleeve 50a encircling the reduced portion of the rod between the heads. Each section is provided with packing rings 50h, and a shell 5la is arranged between the heads, the out-er face of the shell bearing against the inner face of the cylinder. The shells 50a and 51a hold the sections in proper position, and prevent the admission of steam between the sections.

lVhen the piston or plunger is at the end of its stroke in either direction, the sections or heads 50 or 5l of the piston uncover the exhaust openings or slots 3 as shown in Fig. l. The movable heads #t3 and la of the cylinder, are of less diameter than the piston7 so that the actual length of the cylinderl is not al'ected by the adjustment of the heads, but only the clearance between the ends of the piston and the ends of the cylinder. The manner of adjustment may be by other means than movable heads for the cylinder. As for instance in Fig. 2, the clearance is varied by means ot' movable heads in the piston or plunger. The cylinder is provided with a. central annular series of exhaust openings 56, and with inlet openings 57 and 5S at the ends of the cylinder and the openings 56 communicate with the annular chamber 59, Which corresponds to chamber le The chamber 59 communicates With the atmosphere by means of a passage 60.

The piston shown in EiO'. 2 is composed of a sleeve 6l, having a central transverse Web 62, to which is connected the piston rod 63. The sleeve 6l is approximately one-half the length of the cylinder, so that the passages 56 are uncovered just as the piston reaches the end of its stroke in either direction. A movablehead is arranged upon each side of the Web 62, each head 64( and 65 being slidable in the sleeve 6l. The head 64 is provided With a central opening for receiving a bolt 66, threaded into a socket 69 in the adjacent end otl the piston rod. 'Ihe bolt is provided With a collar 67 on the inner side of the head, and a jamb nut 68 is provided With a central opening for receiving the piston rod 6?, and bolts 70 are threaded into bosses 71 on the head. Each bolt is passed through the Web 62 and is provided With a collar 70a on one side of the web, and with a jamb nut 72 on thev other side. The heads may thus be adjusted toward and from the web and the inlets 57 and 50 open into the space between the ends of the cylinder and the movable heads. The head 64 is adjusted by turning the bolt 66, and the head 65 by turning the bolts 70. The operation is the same as in the construction of Fig. l, and the valves coperating with the inlet ports 57 and 58 may be of any usual or desired construction.

I claim l. In a double acting, reciprocating, center discharge, steam engine the combination with a cylinder having inlet ports at its ends, and an annular chamber intermediate its ends and at its approximate center and an annular series of exhaust ports opening into the chamber, and aA piston adapted to over run and control said exhaust ports, a rod connected with the piston and extending through one head of the cylinder, the cylinder having each of its heads internally recessed7 said recesses being cylindrical and of equal cross section throughout and of less cross section than the piston, a head movable in each of the recesses, means for moving the head in the recesses remote from the piston rod, a sleeve encircling the piston rod and rotatable thereon and extending through the adjacent head of the cylinder and the adjacent movable head and having a threaded portion engaging the said movable head to move the said head when the sleeve is rotated. j

2. In a double acting reciprocating steam engine, the combination of a cylinder and a piston operating Within the cylinder, each of the said elements having heads, the heads of one of the said elements being adjustable in the direction of length of the cylinder, whereby the clearance may be varied to increase or diminish the compression, the movable heads being in iixed relation to the elements with which they are associated in their different adjustments.

3. In a double acting reciprocating steam engine, the combination of a cylinder and a piston movable therein, each of the said elements having heads, sundry of the said heads being adjustable in the direction of length of the cylinder' to vary the Working length of the cylinder at each end thereof, said adjustable heads being in fixed relation to the elements with which they are respectively associated in their different adjustments.

MARTIN A. GREEN. Witnesses:

C. E. TRAINOR, SoLoN C. KEMON.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents,

' Washington, D. C. 

